Prelminary

MB91401

2004.11.12

Notes as device

Treatment of Unused Input Pins

It causes the malfunction that the unused input terminal is made open, and do the processing such as 1 stack or 0 stacks.

About Mode pins (MDI2 to MDI0)

Connect these pins with the input buffer by 1 to 1 to prevent the malfunction by the noise, and connect directly to VDD or VSS outside of ASIC.

Operation at start-up

Specify set initialization reset (INIT) with the terminal INITXI when you turn on the power supply.

Moreover, connect "L" level input to the terminal INITXI until the input clock is steady.

About watch dog timer

The watchdog timer function of this macro monitors a program to check whether it delays a reset within a certain period of time. If the program runs out of control and fails to delay the reset, the watchdog timer function resets the CPU.

Therefore, it keeps operating until reset is specified when the watchdog timer function is made effective once.

Exceptionally, the reset postponement is automatically done under the condition that the program execution of CPU stops. Refer to the paragraph of the function explanation of the watchdog timer for the condition of applying to this exception.

There is a possibility that watchdog reset is not generated when entering the above-mentioned state by the reckless driving of the system. In that case, please specify reset (INIT) from external INITX terminal.

Restrictions

Clock control block

Secure the clock stability waiting time at "L" input to INITXI.

When entering the standby mode, use the following sequences after using the synchronous standby mode

(TBCR:set at the bit8 SYNCS bit of timebase counter control register).

(LDI

#value_of_standby, R0)

; Value_of standby is write data to STCR.

(LDI

#_STCR, R12)

; _STCR is address (481H) of STCR.

STB

R0, @R12

; Write to standby control register (STCR).

LDUB

@R12, R0

; STCR read for synchronous standby

LDUB

@R12, R0

; Dummy re-read of STCR

NOP

 

 

NOP

 

 

NOP

NOP

NOP

In addition, set the I-flag and the ILM and ICR registers to branch to an interrupt handler when the interrupt handler triggers the microcontroller to return from the standby mode.

Please do not do the following when the monitor debugger is used.

Please do not set the break point to the above-mentioned instruction row.

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Fujitsu MB91401 Treatment of Unused Input Pins, About Mode pins MDI2 to MDI0, Operation at start-up, About watch dog timer

MB91401 specifications

The Fujitsu MB91401 microcontroller is a versatile device designed for automotive applications, embedded systems, and industrial control. It belongs to the MB91400 series, known for its robustness and efficiency. This series integrates advanced features and technologies that cater to a wide variety of real-time applications.

One of the standout features of the MB91401 is its 32-bit RISC architecture, which operates at clock speeds up to 40 MHz. This high-performance core enables rapid processing and data handling, making it suitable for demanding applications. The microcontroller is equipped with a generous amount of Flash memory, allowing developers to store essential firmware and applications directly on the chip, enhancing reliability and reducing design complexity.

Another key characteristic is its extensive memory configuration, which includes SRAM for data storage and EEPROM for non-volatile data retention. This combination provides flexibility for developers, enabling them to tailor the memory allocation based on specific application requirements.

The MB91401 is designed with a focus on peripheral integration. It features multiple I/O ports, timer units, and A/D converters, making it an ideal choice for applications that require precise timing and analog signal processing. The analog-to-digital converters offer high resolution and fast conversion speeds, which are critical in automotive and industrial control systems where accuracy is paramount.

Safety is a critical consideration in automotive applications, and the MB91401 addresses this with built-in diagnostic features and error detection capabilities. These features help ensure that the application remains functional and safe under various operating conditions.

In terms of connectivity, the microcontroller supports various communication protocols, including CAN, UART, and SPI, facilitating seamless integration with other systems and devices. This is particularly important in automotive applications where communication between different electronic control units (ECUs) is essential for overall system functionality.

The Fujitsu MB91401 is also designed for low power consumption, making it suitable for battery-operated devices and energy-sensitive applications. Its various power-saving modes allow developers to optimize the system's performance while extending operational life.

In summary, the Fujitsu MB91401 is a powerful and flexible microcontroller that combines high-performance processing with extensive peripheral support and safety features. Its robust architecture and energy-efficient design make it an excellent choice for a wide range of automotive and industrial applications, promoting both reliability and innovation in embedded system development.